Method of adhering rubber to brass



lfatented May 6, 1941 UNITED STAT METHOD OF ADHERJNG RUBBER T BRASS James W. Schade, Akron, Ohio, assignor to The B. F. Goodrich Company, New York, N. Y., a

corporation of New York No Drawing. Application December 16, 1937,

Serial N0. 180,200

This invention relates to the adhesion of rub her to brass, and has as its object to provide a method whereby rubber is adhered to an uncorroded brass surface. v

It. has long been known that rubber will adhere directly to brass containing about 65% of copper and 35% of zinc." It has been common practice, therefore, to adhere rubber to other myinvention, a rubber stock was prepared containing rubber 26.88 parts by weight, zinc oxide 69.04 partacarbon black 1.40 parts, sulfur 2.44 parts,'and methylene para-toluidine 0.24 part. A piece of iron was plated with brass, dried, im-

' merse'd momentarily in a bath of molten sulfur metals, especially iron, by depositing a layer of;

brass on theiron and adhering the rubber-there to. the presence of the moisture present in theat- Brass, however, corrodes very rapidly. In u I her from the metal without tearing the stock.

mosphere, brass is corroded to such an extent will no longer adhere when cured against rubber.

The rubber ,must therefore be adhered a'ssoon as and allowed to cool. A sheet of the stock preparedfabove was cured against the sulfur-coated bras surface in a press for minutes at 292 F.

When the. composite article was tested, it was found that it was impossible to separate the rub- The method 'ofthis invention may be practiced with equal success by using an adhesive such as possible after the brass, is applied to the metal,"

even slight delays often -seriously affccting' the adhesion. Attempts to cover the surface of'the brass with a moisture-proof coating have oftenthe same time produce excellent adhesion. The sulfur is usually applied by dipping the brassor brass-plated article in a bath of molten sul-v fur. The protective sulfur coating should be 30.

[ surface which comprises covering the brass with a thin, continuous film consisting essentially of rather thin, as a very thick layer'scmetimes produces undesirably hard rubber when a rubber stock is cured in contact therewith, To assist in the formation of a thin sulfur layer, an introfier such as naphthalene, chloronaphthalene, di-

phenyl, dibenzyl, or trlphenyl phosphate may be added to the molten sulfur.

fur, and for that reason are often used to assist in the impregnation of fibrous materials with sulfur. They are employed in this process because the increased fluidity of the sulfur bath,

Introfiers havethe property of reducing the viscosity of molten sul-' phate being sufiicient while naphthalene is often used in proportions up to 10%.

As a specific embodimentof one modification of a rubber cement or rubber isomer cement betweenthe rubber and the sulfur surface. 7

The term rubber isused in the specification andmyself strictly thereto, for it will be obvious to those skilled in the art that many modifications are within the spirit and scope of the invention as defined in the appended claims.

' Iclaim: I A 1. The method of adhering rubber to a brass sulfur, in direct contact with the brass surface, superposing the rubber, -a'nd subjecting the assemblage to heat and pressure.

2. The'method of adhering rubber to a brass 'surfacewhichicomprises depositing from a bath of molten sulfur a thin, continuous film of sulfur upon the brass,- superposi'ng the rubber and subjecting the assemblage 'toheat and pressure.

3. The methodof adhering rubber to a'brass surface which comprises depositing from a bath- 

